Low-resistance contact to silicon having a titanium silicide interface and an amorphous titanium carbonitride barrier layer

ABSTRACT

A contact structure incorporating an amorphous titanium nitride barrier layer formed via low-pressure chemical vapor deposition (LPCVD) utilizing tetrakis-dialkylamido-titanium, Ti(NMe 2 ) 4 , as the precursor. The contact structure is fabricated by etching a contact opening through an dielectric layer down to a diffusion region to which electrical contact is to be made. Titanium metal is deposited over the surface of the wafer so that the exposed surface of the diffusion region is completely covered by a layer of the metal. At least a portion of the titanium metal layer is eventually converted to titanium silicide, thus providing an excellent conductive interface at the surface of the diffusion region. A titanium nitride barrier layer is then deposited using the LPCVD process, coating the walls and floor of the contact opening. Chemical vapor deposition of polycrystalline silicon or of a metal follows.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of application Ser. No.09/495,534, filed Jan. 31, 2000, pending, which is a continuation ofapplication Ser. No. 09/012,685, filed Jan. 23, 1998, now U.S. Pat. No.6,081,034, issued Jun. 27, 2000, which is a continuation of applicationSer. No. 08/509,708, filed Jul. 31, 1995, now U.S. Pat. No. 5,723,382,issued Mar. 3, 1998; which is a continuation-in-part of U.S. application08/228,795, filed Apr. 15, 1994, now abandoned, which is a continuationof now abandoned U.S. application 07/898,059, filed Jun. 12, 1992.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to integrated circuit manufacturingtechnology and, more specifically, to structures for making lowresistance contact through a dielectric layer to a diffusion region inan underlying silicon layer. The structures include an amorphoustitanium nitride barrier layer that is deposited via chemical vapordeposition.

[0004] 2. State of the Art

[0005] The compound titanium nitride (TiN) has numerous potentialapplications because it is extremely hard, chemically inert (although itreadily dissolves in hydrofluoric acid), an excellent conductor,possesses optical characteristics similar to those of gold, and has amelting point around 3000° C. This durable material has long been usedto gild inexpensive jewelry and other art objects. However, during thelast ten to twelve years, important uses have been found for TiN in thefield of integrated circuit manufacturing. Not only is TiN unaffected byintegrated circuit processing temperatures and most reagents, it alsofunctions as an excellent barrier against diffusion of dopants betweensemiconductor layers. In addition, TiN also makes excellent ohmiccontact with other conductive layers.

[0006] In a common application for integrated circuit manufacture, acontact opening is etched through an insulative layer down to adiffusion region to which electrical contact is to be made. Titaniummetal is then sputtered over the wafer so that the exposed surface ofthe diffusion region is coated. The titanium metal is eventuallyconverted to titanium silicide, thus providing an excellent conductiveinterface at the surface of the diffusion region. A titanium nitridebarrier layer is then deposited, coating the walls and floor of thecontact opening. Chemical vapor deposition of tungsten or polysiliconfollows. In the case of tungsten, the titanium nitride layer providesgreatly improved adhesion between the walls of the opening and thetungsten metal. In the case of the polysilicon, the titanium nitridelayer acts as a barrier against dopant diffusion from the polysiliconlayer into the diffusion region.

[0007] Titanium nitride films may be created using a variety ofprocesses. Some of those processes are reactive sputtering of a titaniumnitride target; annealing of an already deposited titanium layer in anitrogen ambient; chemical vapor deposition at high temperature and atatmospheric pressure, using titanium tetrachloride, nitrogen andhydrogen as reactants; and chemical vapor deposition at low-temperatureand at atmospheric pressure, using ammonia and Ti(NR₂)₄ compounds asprecursors. Each of these processes has its associated problems.

[0008] Both reactive sputtering and nitrogen ambient annealing ofdeposited titanium result in films having poor step coverage, which arenot useable in submicron processes. Chemical vapor deposition (CVD)processes have an important advantage in that conformal layers of anythickness may be deposited. This is especially advantageous inultra-large-scale-integration circuits, where minimum feature widths maybe smaller than 0.5 μm. Layers as thin as 10 Å may be readily producedusing CVD. However, TiN coatings prepared using the high-temperatureatmospheric pressure CVD (APCVD) process must be prepared attemperatures between 900-1000° C. The high temperatures involved in thisprocess are incompatible with conventional integrated circuitmanufacturing processes. Hence, depositions using the APCVD process arerestricted to refractory substrates such as tungsten carbide. Thelow-temperature APCVD, on the other hand, though performed within atemperature range of 100-400° C. that is compatible with conventionalintegrated circuit manufacturing processes, is problematic because theprecursor compounds (ammonia and Ti(NR₂)₄) react spontaneously in thegas phase. Consequently, special precursor delivery systems are requiredto keep the gases separated during delivery to the reaction chamber. Inspite of special delivery systems, the highly spontaneous reaction makesfull wafer coverage difficult to achieve. Even when achieved, thedeposited films tend to lack uniform conformality, are generallycharacterized by poor step coverage, and tend to deposit on everysurface within the reaction chamber, leading to particle problems.

[0009] U.S. Pat. No. 3,807,008, which issued in 1974, suggested thattetrakis dimethylamino titanium, tetrakis diethylamino titanium, ortetrakis diphenylamino titanium might be decomposed within a temperaturerange of 400-1,200° C. to form a coating on titanium-containingsubstrates. It appears that no experiments were performed to demonstratethe efficacy of the suggestion, nor were any process parametersspecifically given. However, it appears that the suggested reaction wasto be performed at atmospheric pressure.

[0010] In U.S. Pat. No. 5,178,911, issued to R. G. Gordon, et al., achemical vapor deposition process is disclosed for creating thin,crystalline titanium nitride films using tetrakis-dimethylamido-titaniumand ammonia as precursors.

[0011] In the J. Appl. Phys. 70(7) October 1991, pp 3,666-3,677, A. Katzand colleagues describe a rapid-thermal, low-pressure, chemical vapordeposition (RTLPCVD) process for depositing titanium nitride films,which, like those deposited by the process of Gordon, et al., arecrystalline in structure.

SUMMARY OF THE INVENTION

[0012] This invention constitutes a contact structure incorporating anamorphous titanium nitride barrier layer formed via low-pressurechemical vapor deposition (LPCVD) utilizingtetrakis-dialkylamido-titanium, Ti(NMe₂)₄, as the precursor. Althoughthe barrier layer compound is primarily amorphous titanium nitride, itsstoichiometry is variable, and it may contain carbon impurities inamounts which are dependent on deposition and post-depositionconditions. The barrier layers so deposited demonstrate excellent stepcoverage, a high degree of conformality, and an acceptable level ofresistivity. Because of their amorphous structure (i.e., having nodefinite crystalline structure), the titanium nitride layer acts as anexceptional barrier to the migration of ions or atoms from a metal layeron one side of the titanium carbonitride barrier layer to asemiconductor layer on the other side thereof, or as a barrier to themigration of dopants between two different semiconductor layers whichare physically separated by the barrier layer.

[0013] The contact structure is fabricated by etching a contact openingthrough a dielectric layer down to a diffusion region to whichelectrical contact is to be made. Titanium metal is deposited over thesurface of the wafer so that the exposed surface of the diffusion regionis completely covered by a layer of the metal. Sputtering is the mostcommonly utilized method of titanium deposition. At least a portion ofthe titanium metal layer is eventually converted to titanium silicide,thus providing an excellent conductive interface at the surface of thediffusion region. A titanium nitride barrier layer is then depositedusing a low-pressure chemical vapor deposition (LPCVD) process, coatingthe walls and floor of the contact opening. Chemical vapor deposition(CVD) of polycrystalline silicon, or of a metal, such as tungsten,follows, and proceeds until the contact opening is completely filledwith either polycrystalline silicon or the metal. In the case of thepolysilicon, which must be doped with N-type or P-type impurities torender it conductive, the titanium nitride layer acts as a barrieragainst dopant diffusion from the polysilicon layer into the diffusionregion. In the case of CVD tungsten, the titanium nitride layer protectsthe junction from reactions with precursor gases during the CVDdeposition process, provides greatly improved adhesion between the wallsof the opening and the tungsten metal, and prevents the diffusion oftungsten atoms into the diffusion region.

[0014] Deposition of the titanium nitride barrier layer takes place in alow-pressure chamber (i.e. a chamber in which pressure has been reducedto less than 100 torr prior to deposition), and utilizes a metal-organictetrakis-dialkylamido-titanium compound as the sole precursor. Any noblegas, as well as nitrogen or hydrogen, or a mixture of two or more of theforegoing may be used as a carrier for the precursor. The wafer isheated to a temperature within a range of 200-600° C. Precursormolecules which contact the heated wafer are pyrolyzed to form titaniumnitride containing variable amounts of carbon impurities, which depositsas a highly conformal film on the wafer.

[0015] The carbon content of the barrier film may be minimized byutilizing tetrakis-dimethylamido-titanium, Ti(NMe₂)₄, as the precursor,rather than compounds such as tetrakis-diethylamido-titanium ortetrakis-dibutylamido-titanium, which contain a higher percentage ofcarbon by weight. The carbon content of the barrier film may be furtherminimized by performing a rapid thermal anneal step in the presence ofammonia.

[0016] The basic deposition process may be enhanced to further reducethe carbon content of the deposited titanium nitride film by introducingone or more halogen gases, or one or more activated species (which mayinclude halogen, NH₃, or hydrogen radicals) into the deposition chamber.Halogen gases and activated species attack the alkyl-nitrogen bonds ofthe primary precursor and convert displaced alkyl groups into volatilecompounds.

[0017] As heretofore stated, the titanium carbonitride films formed bythe instant chemical vapor deposition process are principally amorphouscompounds. Other processes currently in use for depositing titaniumnitride-containing compounds as barrier layers within integratedcircuits result in titanium nitride having crystalline structures. Asatomic and ionic migration tends to occur at crystal grain boundaries,an amorphous film is a superior barrier to such migration.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0018]FIG. 1 is a block schematic diagram of a low-pressure chemicalvapor deposition reactor system;

[0019]FIG. 2 is an X-ray spectrum (i.e., a plot of counts per second asa function of 2-theta);

[0020]FIG. 3 is a cross-sectional view of a contact opening having anarrow aspect ratio that has been etched through an insulative layer toan underlying silicon substrate, the insulative layer and the contactopening having been subjected to a blanket deposition of titanium metal;

[0021]FIG. 4 is a cross-sectional view of the contact opening of FIG. 3following the deposition of an amorphous titanium nitride film;

[0022]FIG. 5 is a cross-sectional view of the contact opening of FIG. 4following an anneal step; and

[0023]FIG. 6 is a cross-sectional view of the contact opening of FIG. 5following the deposition of a conductive material layer.

DETAILED DESCRIPTION OF THE INVENTION

[0024] The integrated circuit contact structure that is the focus ofthis disclosure is unique because of the use of a predominantlyamorphous titanium or titanium carbonitride barrier layer therein. Thelayer is deposited using a low-pressure chemical vapor deposition(LPCVD) process that is the subject of previously filed U.S. patentapplications as heretofore noted.

[0025] The LPCVD process for depositing highly conformal titaniumnitride and titanium carbonitride barrier films will now be brieflydescribed in reference to the low-pressure chemical vapor depositionreactor system depicted in FIG. 1. The deposition process takes place ina cold wall chamber 11. A wafer 12, on which the deposition will beperformed, is mounted on a susceptor plate 13, which is heated to atemperature within a range of 200-600° C. by a heat lamp array 14. Forthe instant process, a carrier gas selected from a group consisting ofthe noble gases and nitrogen and hydrogen is bubbled through liquidtetrakis-dialkylamido-titanium 15 (the sole metal-organic precursorcompound) in a bubbler apparatus 16.

[0026] It should be noted that tetrakis-dialkylamido-titanium is afamily of compounds, of which tetrakis-dimethylamido-titanium,tetrakis-diethylamido-titanium and tetrakis-dibutylamido-titanium havebeen synthesized. Because of its lower carbon content per unit ofmolecular weight, tetrakis-dimethylamido-titanium is the preferredprecursor because it results in barrier films having lower carboncontent. However, any of the three compounds or any combination of thethree compounds will result in highly conformal barrier layers whenpyrolyzed (decomposition by heating) in a CVD deposition chamber. Thesebarrier layers are characterized by an amorphous structure, and by stepcoverage on vertical wall portions near the base of submicron contactopenings having depth-to-width aspect ratios of 3:1 that range from80-90 percent of the horizontal film thickness at the top of theopening.

[0027] Still referring to FIG. 1, the carrier gas, at least partiallysaturated with a vaporized precursor compound, is transported via aprimary intake manifold 17 to a premix chamber 18. Additional carriergas may be optionally supplied to premix chamber 18 via supply tube 19.Carrier gas, mixed with the precursor compound, is then ducted through asecondary intake manifold 20 to a shower head 21, from which they enterthe chamber 11. The precursor compound, upon coming into contact withthe heated wafer, pyrolyzes and deposits as a highly conformal titaniumcarbonitride film on the surface of the wafer 12. The reaction productsfrom the pyrolysis of the precursor compound are withdrawn from thechamber 11 via an exhaust manifold 22. Incorporated in the exhaustmanifold 22 are a pressure sensor 23, a pressure switch 24, a vacuumvalve 25, a pressure control valve 26, a blower 27, and a particulatefilter 28, which filters out solid reactants before the exhaust isvented to the atmosphere. During the deposition process, the pressurewithin chamber 11 is maintained at a pressure of less than 100 torr andat a pressure of less than 1 torr by pressure control components 23, 24,25, 26, and 27. The process parameters that are presently deemed to beoptimum, or nearly so, are a carrier gas flow through secondary intakemanifold 20 of 400 standard cubic centimeters per minute (scc/m), adeposition chamber temperature of 425° C., and a flow of carrier gasthrough bubbler apparatus 16 of 100 scc/m, with the liquid precursormaterial 15 being maintained at a constant temperature of approximately40° C.

[0028] Thus, the carrier gas (or gases) and the vaporized precursorcompound are then gradually admitted into the chamber until the desiredpressure and gas composition is achieved. The reaction, therefore, takesplace at a constant temperature, but with varying gas partial pressuresduring the initial phase of the process. This combination of processparameters is apparently responsible for the deposition of titaniumcarbonitride having a predominantly amorphous structure as the precursorcompound undergoes thermal decomposition. The X-ray spectrum of FIG. 2is indicative of such an amorphous structure. Both the peak at a 2-thetavalue of 36, which is characteristic of titanium nitride having a (111)crystal orientation, and the peak at a 2-theta value of 41, which ischaracteristic of titanium nitride having a (200) crystal orientation,are conspicuously absent from the spectrum. Such a spectrum indicatesthat there is virtually no crystalline titanium nitride in the analyzedfilm. Incidentally, the peak at a 2-theta value of 69 is representativeof silicon.

[0029] Although the compound deposited on the wafer with this processmay be referred to as titanium carbonitride (represented by the chemicalformula TiC_(x)N_(y)), the stoichiometry of the compound is variable,depending on the conditions under which it is deposited. The primaryconstituents of films deposited using the new process andtetrakis-dimethylamido-titanium as the precursor are titanium andnitrogen, with the ratio of nitrogen atoms to carbon atoms in the filmfalling within a range of 5:1 to 10:1. In addition, upon exposure to theatmosphere, the deposited films absorb oxygen. Thus the final film maybe represented by the chemical formula TiC_(x)N_(y)O_(z). The carbon andoxygen impurities affect the characteristics of the film in at least twoways. Firstly, the barrier function of the film is enhanced. Secondly,the carbon and oxygen impurities dramatically raise the resistivity ofthe film. Sputtered titanium nitride has a bulk sheet resistivity ofapproximately 75 μohm-cm, while the titanium carbonitride filmsdeposited through the CVD process disclosed herein have bulk sheetresistivities of 2,000 to 50,000 μohm-cm. In spite of this dramaticincrease in bulk resistivity, the utility of such films as barrierlayers is largely unaffected, due to the characteristic thinness ofbarrier layers used in integrated circuit manufacture. A simple analysisof the contact geometry for calculating various contributions to theoverall resistance suggests that metal (e.g., tungsten) plug resistanceand metal-to-silicon interface resistance play a much more significantrole in overall contact resistance than does the barrier layer.

[0030] There are a number of ways by which the basic LPCVD process maybe enhanced to minimize the carbon content of the deposited barrierfilm.

[0031] The simplest way is to perform a rapid thermal anneal step in thepresence of ammonia. During such a step, much of the carbon in thedeposited film is displaced by nitrogen atoms.

[0032] The basic deposition process may be enhanced to further reducethe carbon content of the deposited titanium nitride film by introducingan activated species into the deposition chamber. The activated speciesattacks the alkyl-nitrogen bonds of the primary precursor, and convertsdisplaced alkyl groups into volatile compounds. The activated species,which may include halogen, NH₃, or hydrogen radicals, or a combinationthereof, are generated in the absence of the primary precursor at alocation remote from the deposition chamber. Remote generation of theactivated species is required because it is not desirable to employ aplasma CVD process, as Ti(NR₂)₄ is known to break down in plasma,resulting in large amounts of carbon in the deposited film. A highcarbon content will elevate the bulk resistivity of the film to levelsthat are unacceptable for most integrated circuit applications. Theprimary precursor molecules and the activated species are mixed,preferably, just prior to being ducted into the deposition chamber. Itis hypothesized that as soon as the mixing has occurred, the activatedspecies begin to tear away the alkyl groups from the primary precursormolecules. Relatively uncontaminated titanium nitride deposits on theheated wafer surface.

[0033] Alternatively, the basic deposition process may be enhanced tolower the carbon content of the deposited titanium nitride films byintroducing a halogen gas, such as F₂, Cl₂ or Br₂, into the depositionchamber. The halogen gas molecule attacks the alkyl-nitrogen bonds ofthe primary precursor compound molecule and converts the displaced alkylgroups into a volatile compound. The halogen gas is admitted to thedeposition chamber in one of three ways. The first way is to admithalogen gas into the deposition chamber before the primary precursorcompound is admitted. During this “pre-conditioning” step, the halogengas becomes adsorbed on the chamber and wafer surfaces. The LPCVDdeposition process is then performed without admitting additionalhalogen gas into the deposition chamber. As a first alternative, thehalogen gas and vaporized primary precursor compound are admitted intothe deposition chamber simultaneously. Ideally, the halogen gas andvaporized primary precursor compound are introduced into the chamber viaa single shower head having separate ducts for both the halogen gas andthe vaporized primary precursor compound. Maintaining the halogen gasseparate from the primary precursor compound until it has entered thedeposition chamber prevents the deposition of titanium nitride on theshower head. It is hypothesized that as soon as the mixing has occurred,the halogen molecules attack the primary precursor molecules and beginto tear away the alkyl groups therefrom. Relatively uncontaminatedtitanium nitride deposits on the heated wafer surface. As a secondalternative, halogen gas is admitted into the chamber both before andduring the introduction of the primary precursor compound.

[0034] As heretofore stated, the titanium nitride or titaniumcarbonitride films deposited by the described LPCVD process arepredominantly amorphous compounds. Other processes currently in use fordepositing titanium nitride-containing compounds as barrier layerswithin integrated circuits result in titanium nitride having crystallinestructures. As atomic and ionic migration tends to occur at crystalgrain boundaries, an amorphous film is a superior barrier to suchmigration.

[0035] Referring now to FIG. 3, which is but a tiny cross-sectional areaof a silicon wafer undergoing an integrated circuit fabrication process,a contact opening 31 having a narrow aspect ratio has been etchedthrough a borophosphosilicate glass (BPSG) layer 32 to a diffusionregion 33 in an underlying silicon substrate 34. A titanium metal layer35 is then deposited over the surface of the wafer. Because titaniummetal is normally deposited by sputtering, it deposits primarily onhorizontal surfaces. Thus, the portions of the titanium metal layer 35on the walls and at the bottom of the contact opening 31 are muchthinner than the portion that is outside of the opening on horizontalsurfaces. The portion of titanium metal layer 35 that covers diffusionregion 33 at the bottom of contact opening 31 will be denoted 35A. Atleast a portion of the titanium metal layer 35A will be converted totitanium silicide in order to provide a low-resistance interface at thesurface of the diffusion region.

[0036] Referring now to FIG. 4, a titanium nitride barrier layer 41 isthen deposited utilizing the LPCVD process, coating the walls and floorof the contact opening 31.

[0037] Referring now to FIG. 5, a high-temperature anneal step in anambient gas such as nitrogen, argon, ammonia, or hydrogen is performedeither after the deposition of the titanium metal layer 35 or after thedeposition of the titanium nitride barrier layer 41. Rapid thermalprocessing (RTP) and furnace annealing are two viable options for thisstep. During the anneal step, the titanium metal layer 35A at the bottomof contact opening 31 is either partially or completely consumed byreaction with a portion of the upper surface of the diffusion region 33to form a titanium silicide layer 51. The titanium silicide layer 51,which forms at the interface between the diffusion region 33 andtitanium metal layer 35A, greatly lowers contact resistance in thecontact region.

[0038] Referring now to FIG. 6, a low-resistance conductive layer 62 ofmetal or heavily-doped polysilicon may be deposited on top of thetitanium nitride barrier layer 41. Tungsten or aluminum metal iscommonly used for such applications. Copper or nickel, though moredifficult to etch than aluminum or tungsten, may also be used.

[0039] Although only several embodiments of the inventive process havebeen disclosed herein, it will be obvious to those having ordinary skillin the art that modifications and changes may be made thereto withoutaffecting the scope and spirit of the invention as claimed.

What is claimed is:
 1. A process of making a contact structure for anintegrated circuit comprising: providing a silicon region on a surfaceof a semiconductor wafer for making electrical contact thereto;depositing a dielectric layer over at least a portion of the siliconregion; etching a contact opening through said dielectric layer forexposing a portion of said silicon region, said contact opening having aside wall; depositing a titanium metal layer within the contact openingfor covering the portion of the silicon region exposed by the contactopening; depositing an amorphous titanium carbonitride film havingsubstantially no definite crystalline structure and having substantiallyno crystalline titanium therein, said amorphous titanium carbonitridefilm for lining the side wall of the contact opening to overlay thetitanium metal layer covering the portion of the silicon region exposedby the contact opening; and filling at least a portion of the contactopening using a conductive material.
 2. The process of claim 1 , whereindepositing the amorphous titanium carbonitride film comprises a chemicalvapor deposition process.
 3. The process of claim 2 , wherein thechemical vapor deposition process includes: evacuating a depositionchamber to a pressure of less than about 100 torr; heating thesemiconductor wafer to a temperature within a range of about 200° C. toabout 600° C.; maintaining the temperature of the semiconductor waferwithin the range of about 200° C. to about 600° C.; admitting anorganometallic precursor compound into the deposition chamber, theorganometallic precursor compound including atetrakis-dialkylamido-titanium compound; decomposing the organometallicprecursor compound at least near the surface of the semiconductor wafer;and depositing the amorphous titanium carbonitride film havingsubstantially no definite crystalline structure and having substantiallyno crystalline titanium therein on at least a portion of the surface ofthe semiconductor wafer and within at least a portion of the contactopening.
 4. The process of claim 3 , wherein said organometallicprecursor compound comprises tetrakis-dimethylamido-titanium.
 5. Theprocess of claim 1 , wherein the conductive material comprises a metalselected from the group consisting of tungsten, aluminum, copper andnickel.
 6. The process of claim 1 , wherein the conductive materialcomprises doped polycrystalline silicon.
 7. The process of claim 1 ,further comprising: heating the semiconductor wafer; and reacting atleast a portion of the titanium metal layer covering the portion of thesilicon region exposed by the contact opening with the silicon region toform a titanium silicide layer.
 8. The process of claim 7 , wherein thereacting the at least a portion of the titanium metal layer with thesilicon region occurs prior to depositing the amorphous titaniumcarbonitride film having substantially no definite crystalline structureand having substantially no crystalline titanium nitride therein.
 9. Theprocess of claim 7 , wherein the reacting the at least a portion of thetitanium metal layer with the silicon region occurs subsequent todepositing the amorphous titanium carbonitride film having substantiallyno definite crystalline structure and having substantially nocrystalline titanium nitride therein.
 10. The process of claim 1 ,further comprising: subjecting the amorphous titanium carbonitride filmhaving substantially no definite crystalline structure and havingsubstantially no crystalline titanium therein to rapid thermalprocessing in the presence of one or more gases selected from the groupconsisting of nitrogen, hydrogen and the noble gases.
 11. A process forfabricating a contact structure for an integrated semiconductor circuitcomprising: providing a silicon region on a surface of a semiconductorwafer for electrical contact thereto; depositing a dielectric layer overthe silicon region; etching a contact opening through said dielectriclayer for exposing a portion of said silicon region, said contactopening having a side wall; depositing a titanium metal layer within thecontact opening to cover the portion of the silicon region exposed bythe contact opening; depositing an amorphous titanium carbonitride filmhaving substantially no crystalline titanium therein lining the sidewall of the contact opening and overlaying the titanium metal layercovering the portion of the silicon region exposed by the contactopening; and filling at least a portion of the contact opening using aconductive material.
 12. The process of claim 11 , wherein depositingthe amorphous titanium carbonitride film includes a chemical vapordeposition process.
 13. The process of claim 12 , wherein the chemicalvapor deposition process includes: evacuating a deposition chamber to apressure of less than about 100 torr; heating the semiconductor wafer toa temperature within a range of about 200° to about 600° C.; maintainingthe temperature of the semiconductor wafer; admitting an organometallicprecursor compound into the deposition chamber, the organometallicprecursor compound including a tetrakis-dialkylamido-titanium compound;decomposing the organometallic precursor compound at or near the surfaceof the semiconductor wafer; and depositing the amorphous titaniumcarbonitride film having substantially no crystalline titanium nitridetherein on at least a portion of the surface of the semiconductor waferand within the contact opening.
 14. The process of claim 13 , whereinsaid organometallic precursor compound comprisestetrakis-dimethylamido-titanium.
 15. The process of claim 11 , whereinthe conductive material comprises a metal selected from the groupconsisting of tungsten, aluminum, copper and nickel.
 16. The process ofclaim 11 , wherein the conductive material comprises dopedpolycrystalline silicon.
 17. The process of claim 11 , furthercomprising: heating the semiconductor wafer; and reacting at least aportion of the titanium metal layer covering the portion of the siliconregion exposed by the contact opening with the silicon region to form atitanium silicide layer.
 18. The process of claim 17 , wherein thereacting the at least a portion of the titanium metal layer with thesilicon region occurs prior to depositing the amorphous titaniumcarbonitride film having substantially no crystalline titanium therein.19. The process of claim 17 , wherein the reacting the at least aportion of the titanium metal layer with the silicon region occurssubsequent to depositing the amorphous titanium carbonitride film havingsubstantially no crystalline titanium therein.
 20. The process of claim11 , further comprising: subjecting the amorphous titanium carbonitridefilm having substantially no crystalline titanium therein to rapidthermal processing in the presence of one or more gases selected fromthe group consisting of nitrogen, hydrogen and the noble gases.
 21. Aprocess for fabricating a contact structure in a silicon region in anintegrated semiconductor circuit on a surface of a semiconductor wafercomprising: depositing a dielectric layer over at least a portion ofsaid silicon region; etching a contact opening through said dielectriclayer, said contact opening having a side wall and terminating in abottom exposing a portion of said silicon region; depositing a titaniummetal layer within the contact opening covering the portion of thesilicon region exposed by the bottom of the contact opening; depositingan amorphous titanium carbonitride film having substantially nocrystalline titanium nitride therein on the side wall of the contactopening and over the titanium metal layer; and filling at least aportion of the contact opening using a conductive material.
 22. Theprocess of claim 21 , wherein depositing the amorphous titaniumcarbonitride film having substantially no crystalline titanium nitridetherein comprises a chemical vapor deposition process.
 23. The processof claim 22 , further comprising: evacuating a deposition chamber to apressure of less than about 100 torr; heating said semiconductor waferto a temperature in a range of about 200° C. to about 600° C.; anddepositing the amorphous titanium carbonitride film having substantiallyno definite crystalline titanium nitride therein using an organometallicprecursor compound comprising tetrakis-dialkylamido-titanium in thedeposition chamber by thermal decomposition thereof at or near saidsurface of said semiconductor wafer.
 24. The process of claim 23 ,wherein said organometallic precursor compound comprisestetrakis-dimethylamido-titanium.
 25. The process of claim 21 , whereinsaid conductive material comprises a metal selected from the groupconsisting of tungsten, aluminum, copper and nickel.
 26. The process ofclaim 21 , wherein said conductive material comprises dopedpolycrystalline silicon.
 27. The process of claim 21 , furthercomprising: forming a titanium silicide layer by heating saidsemiconductor wafer and reacting at least a portion of the titaniummetal layer with said silicon region.
 28. The process of claim 27 ,wherein the titanium silicide layer is formed prior to the depositingthe amorphous titanium carbonitride film having substantially nocrystalline titanium nitride.
 29. The process of claim 27 , wherein thetitanium silicide layer is formed subsequent to the depositing theamorphous titanium carbonitride film having substantially no crystallinetitanium nitride.
 30. The process of claim 21 , further comprising:thermally processing the amorphous titanium carbonitride film in anatmosphere in said deposition chamber including one or more gasesselected from the group consisting of nitrogen, hydrogen and the noblegases.
 31. A process for fabricating a contact structure in a siliconregion on a surface of a semiconductor wafer for an integratedsemiconductor circuit comprising: depositing a dielectric layer over atleast a portion of said silicon region; etching a contact openingthrough said dielectric layer, said contact opening having a side walland terminating in a bottom exposing a portion of said silicon region;depositing a titanium metal layer within the contact opening coveringthe portion of the silicon region exposed by the bottom of the contactopening; depositing an amorphous titanium carbonitride film havingsubstantially no crystalline titanium nitride therein detectable in anX-ray spectrum thereof on the side wall of the contact opening and overthe titanium metal layer; and filling at least a portion of the contactopening using a conductive material.
 32. The process of claim 31 ,wherein depositing the amorphous titanium carbonitride film havingsubstantially no crystalline nitride therein detectable in an X-rayspectrum thereof comprises a chemical vapor deposition process.
 33. Theprocess of claim 32 , further comprising: evacuating a depositionchamber to a pressure of less than about 100 torr; heating saidsemiconductor wafer to a temperature in a range of about 200° C. toabout 600° C.; and depositing the amorphous titanium carbonitride filmhaving substantially no crystalline titanium nitride therein detectablein an X-ray spectrum thereof using an organometallic precursor compoundcomprising tetrakis-dialkylamido-titanium in the deposition chamber bythermal decomposition near said surface of said semiconductor wafer. 34.The process of claim 33 , wherein said organometallic precursor compoundcomprises tetrakis-dimethylamido-titanium.
 35. The process of claim 31 ,wherein said conductive material comprises a metal selected from thegroup consisting of tungsten, aluminum, copper and nickel.
 36. Theprocess of claim 31 , wherein said conductive material comprises dopedpolycrystalline silicon.
 37. The process of claim 31 , furthercomprising: forming a titanium silicide layer by heating saidsemiconductor wafer and reacting at least a portion of the titaniummetal layer with said silicon region.
 38. The process of claim 37 ,wherein the titanium silicide layer is formed prior to the depositingthe amorphous titanium carbonitride film having substantially nocrystalline titanium nitride therein detectable in an X-ray spectrumthereof.
 39. The process of claim 37 , wherein the titanium silicidelayer is formed subsequent to depositing the amorphous titaniumcarbonitride film having substantially no crystalline titanium nitridetherein detectable in an X-ray spectrum thereof.
 40. The process ofclaim 31 , further comprising: thermally processing the amorphoustitanium carbonitride film in an atmosphere in said deposition chamberincluding one or more gases selected from the group consisting ofnitrogen, hydrogen and the noble gases.